Some of these folks were excellent hunters before they ever appeared on television,some were not and still aren't.The same basic fundamentals for success apply to any hunter regardless of whether you are a television personality or not.
First off to kill big deer you have to hunt where they are,then you have to hunt smart and hunt hard.If a lot of variables are controlled such as pressure,age structure,buck to doe ratio's,food sources,scouting by either you or a guide or outfitter.With these variables tended to in the right way a very average hunter can be made to look like an exceptional hunter.